The Feds have used the Antiquites Act to go after defacers of public lands, and if she tramped around painting in canyons with petroglyphs or pictographs, they'll have plenty of cause.
A few years ago, some bird-brain fisherman from my state of NC decided to carve his name next to the Descending Sheep panel petroglyphs in a canyon along the CO River below Glen Canyon Dam. He got caught and was successfully prosecuted. Seems like the fine was $10,000, some community service hours, and years of probation.
I truly hope this woman, with her delusions of talent, gets the same for each instance.